"Dog allergies are very similar to human allergies and also produce the same symptoms as human allergies. There are 5 types of dog allergies: food allergy, flea allergy, bacteria allergy, contact allergy and atopy. Here are some basic facts about each of these allergies.
The most common symptom of food allergies is scratching, due to skin irritation. Dog foods contain a host of ingredients which can cause an allergic reaction to your dog. Some of these ingredients are:
Meats: Beef, Chicken, Pork, Lamb, Fish, Eggs
Diary products (Milk)
Grains (Wheat, Whey)
Most dog owners often scold their dog for scratching too much. Any obsessive behavior your dog demonstrates, such as constant scratching, chewing, licking, requires immediate attention. Never assume that this is just a new habit your dog picked up. Dog allergies can make your dog very uncomfortable.
Aside from scratching, some of the other symptoms dogs can experience are:
eye and nose discharge
Itching around the anus
loss of appetite
pawing at their ears or head shaking
Isolating the allergen which causes the allergy is not easy because the dog is usually allergic to one specific ingredient in the food. Therefore, it is a matter of isolating that ingredient. You can try doing this with an elimination diet, which most people don't have the time or energy for. The elimination diet requires preparing specially-cooked meals consisting of a more exotic meat, like rabbit or venison, mixed with rice or potato, which wouldn't normally be found in dog food.
An easier and more modern approach to test for the presence of a food allergy is to try a dog food which contains hydrolyzed proteins, such as Purinas HA or Hills z/d. Hydrolyzed proteins are broken down into molecules so small, they can't affect the immune system, which is what causes the allergy. If the allergy goes away while your dog is on this diet (which would take about 8 weeks), then he most likely is suffering from a food allergy. At this point, you would start to re-introduce the possible allergens one by one (individual meats, wheat, corn, milk, etc.) for a period of two weeks each. If the symptoms return, it is most likely due to the ingredient being introduced at that time. You should look out for that ingredient on dog food labels in future purchases.
Atopy (inhalant allergy)
Atopy is the most common of all dog allergies, which is caused by environmental factors, such as dust mites, molds, house dust, human dander, feathers or pollen.
Signs of atopy include excessive chewing, licking and scratching at the face, paws, abdomen, armpits and genital area. Evidence of this behavior can be found in examining your dog's paws, armpits and genital area. Reddish-brown stains develop in these areas due to excessive licking. This may not be evident in dogs with dark coats.
Atopy is not easy to diagnose due to other dog allergies having the same symptoms. Once these other dog allergies (food, flea and contact) have been ruled out, your vet can proceed with testing for the root cause of the atopy. The most accurate method of testing for atopy is Intradermal Skin Testing.
There are many different treatment options for atopy. The best treatment would be avoiding the allergen altogether. If this is not feasible, other treatments include cool water baths with medicated shampoo, antihistamines, allergy shots, corticosteriods or a diet rich in Omega-3 and Omega-6 fatty acids.
Dog allergies to fleas are not caused by the flea itself, but rather the flea's saliva. A common symptom of flea allergies is scratching at the tail area which causes hair loss, scabs and sores. Your vet can easily diagnose a flea allergy by checking for the presence of fleas in the coat. Fleas can be seen by the naked eye. Intradermal Skin Testing can also be used to test for this type of allergy. The most effective products for eliminating fleas are:
Advantage - Flea control for your Dog & CatFrontLine - Flea & Tick
Medication for your Dog & Cat
Capstar- Flea infestation on Dog and Cat
K9 Advantix Flea and Tick Medication (based on dog's weight)
A dog's skin normally harbors Staph bacteria. Usually, this bacteria does not have any affect on your dog but some dogs develop a sensitivity to it causing an allergic reaction. Your dog may develop crusts on the skin and patches of hair loss due to scratching, similar to ring worm. If these patches become infected, your dog will need to be treated with antibiotics.
Contact allergies are the least common of all dog allergies. This type of allergy produces swelling, redness, itching and hair loss. Common contact allergens include flea collars, plastic food bowls, pet sweaters, plants, grass or wool bedding. The best way to diagnose this allergy is if the symptoms continue after ruling out all other allergies. If this is the case, then you must pinpoint the allergen and remove it from your dog's environment."